Reviewed by Daniel Muth

Galileo Observed
Science and the Politics of Belief
By William R. Shea and Mariano Artigas. Science History Publications. 2006. Pp. 212. $30. ISBN 0-8135-356-6.

“Eppur si muove (and yet it does move).” So Galileo most certainly did not say at the end of his infamous trial in 1633. He was, of course, eventually proven right, more or less. But by then he had been in his expensive and ornate grave the better part of a century, having spent the last 11 of his 78 years under house arrest in his palatial estate, following his second trial. The first had been in 1616 and its outcome was then, and has been since, much disputed.

What is not in dispute is that this trial of Galileo is one of the most carefully studied events in the history of science and the Church, one about which endless books and plays have been  written, debating points scored, and cultural battles fought. It is to the political (and too often propagandistic) uses to which the affair has been put that Galileo Observed is addressed. The authors begin with William Draper and Andrew White’s Victorian Era mythologizing about the trial as a major battlefield in their supposed “war of science and religion,” demonstrating that neither trial had much to do with any obscurantist opposition of the Roman Catholic Church to the scientific enterprise or excessive devotion to literalist hermeneutics. Though, to be sure, there were elements of these things in play, as the Church of the time was cautious with regard to developments in cosmology that were sweeping the scientific world.

Nor was it simply a matter of a feckless and arrogant Galileo bringing condemnation on himself, as the authors note when they evaluate Arthur Koestler’s 1959 novel The Sleepwalkers. Though again, it cannot be ignored that Galileo was possessed of an often prickly and difficult persona, refusing to accept Tycho Brahe’s observations of comets and at times belittling Kepler, whose most important scientific achievements Galileo mostly rejected (like most natural philosophers from ancient times, Galileo considered long-distance interactions an impossibility and so discounted Kepler’s claims of lunar gravitational pull as the cause of the tides, preferring his own claim that they resulted from the motion of Earth; he also rejected Kepler’s theory of elliptical planetary motion, preferring the more traditional — and incorrect — assumption of circular orbits).

One by one, Shea, Galileo Professor of History of Science at the University of Padua, and Artigas, who teaches philosophy and theology at the University of Navarra in Spain, judiciously assess the various claims about and interpretations of the trials, from Bertolt Brecht’s 1957 Marxist play (considerably contributed to by the famous actor, Charles Laughton), Life of Galileo, to the Roman Catholic Church’s 1992 expression of regret concerning the Church’s part in the affair. While assessing the various claims, counterclaims, arguments, freshenings-up, soi disant “new” perspectives, mythologizing, etc., the authors carefully portray the known history of Galileo and the events that resulted in his judicial difficulties.

More important than any other factor is that Galileo was a layman presuming to interpret Scripture in the shadow of the Council of Trent, which had concluded in 1563, scarcely a generation earlier. The council, while making no pronouncements on science (Copernicus undertook his major work De Revolutionibus, published in 1543, in no small part in response to a previous council, the Fifth Lateran, from which a request had emanated to theologians and astronomers to aid in correcting the calendar), did pronounce on the authority to interpret Scripture (holding against Protestantism that individual laymen could not do so), and tended to uphold the scholastic mode of discourse, counting the Vulgate more authoritative than older Greek and Hebrew texts of Scripture.

The general tendency of Catholic thought following the council was one of caution, trusting more to literal understandings of the scriptural texts understood to address cosmology or other sciences, suspending “until corrected” both De Revolutionibus and Zuñiga’s Copernican interpretation of certain biblical passages in his Commentary on Job. Both Catholic and Protestant exegetes of the time generally left open the possibility of interpreting such passages “according to the senses,” meaning, for instance, that the sun’s stopping in the sky in Joshua refers to how the event appeared rather than to the non-movement of Earth per se. Such an interpretation, however, would require proof — and this would not be forthcoming until the 18th century in this case. Regardless, Catholic exegetes were expected to be trained theologians and not laymen, however otherwise well educated.

Born the year after Trent concluded, Galileo studied medicine at the University of Pisa. In 1589, he became professor of mathematics there, remaining for the time being a typical Aristotelian. His principal interest, however, was in attaining sure and certain scientific knowledge, and his means of doing so were open to change. In 1592, he was appointed chairman of mathematics in Padua, where he began his most important experiments in mechanics, producing a number of discoveries that would be later published as perhaps his greatest work, Mathematical Discourses and Demonstrations Concerning Two New Sciences. He studied William Gilbert’s works on magnetism and entered into correspondence with Kepler, whom he generally esteemed. Having heard of the discovery of the telescope, he constructed one and, while not the first to aim it at the heavens, quickly became the most celebrated, following the publication of Siderius Nuncius in 1610, wherein he described the moons of Jupiter. His return to Pisa as First Mathematician of the University of Pisa and Philosopher and Mathematician to Grand Duke Cosimo II of Tuscany was followed a year later by a triumphant journey to Rome to be inducted into the Lyncean Academy. He also made the acquaintance of Cardinal Barberini, the future Urban VIII.

While now occupying a prestigious position that removed all financial worry, Galileo soon found that he had exchanged academic freedom in Venice for a Tuscan court awash with envy and intrigue, added to which the Venetians counted his move as a sign of ingratitude. After Galileo issued the Sunspot Letters in 1613, he began for the first time to openly champion Copernicanism. By this time, Tycho’s model of the solar system, in which the planets orbit the sun while the latter, along with the moon, orbits Earth, had gained ascendancy among the intellectuals of Europe. The Church was generally tolerant of any view, so long as it was recognized that there was no conclusive proof that required a reinterpretation of the Scriptures that indicate a fixed Earth. Copernicans were free to speculate, but were required to make clear that they defended only a hypothetical notion, one in which mathematical models predict planetary position, but do not necessarily describe celestial reality.

In his famous Letter to Castelli (a Benedictine and close friend), written in late 1613, Galileo attempted to address a question raised by the Grand Duchess Christina in a casual conversation concerning the biblical orthodoxy of Copernicanism. In the letter, Galileo defended a position to the effect that, when the Bible addresses matters open to sense experience and rational knowledge (as opposed to supernatural realities or matters directly regarding salvation), theologians had better heed demonstrative arguments of natural philosophers and scientists before committing to an interpretation. This position was a venerable one, attributable to St. Augustine himself, and would be accepted by the Second Vatican Council. However, a number of theologians, particularly two Dominican Fathers, Niccolo Lorini and Thommaso Caccini, took umbrage at the notion of theologians being lectured on scriptural interpretation by a layman and passed the letter to the Holy Office. Galileo updated and expanded his argument in A Letter to Grand Duchess Christina in 1615 and began preparations to set out for Rome to defend his position.

Shortly after the latter was written, a book by Carmelite friar Paolo Antonio Foscarini defended the compatibility of Copernicanism with Holy Scripture. The celebrated Cardinal Robert Bellarmine, a distinguished intellectual well versed in natural philosophy, wrote a three-point objection in 1615 countering Foscarini’s position based on an expanded understanding of Trent’s assertions regarding Scripture’s pronouncements of “matters of faith,” that these include historical and empirical, as well as spiritual, matters; and the lack of definitive proof of the veracity of the Copernican thesis. This doomed Galileo’s position. Copernicanism was condemned in March of 1616; Foscarini, only 36, died later that year; and Bellarmine himself, possibly recalling the execution of Giordano Bruno on heresy charges 16 years earlier, personally delivered to Galileo what amounted to a mild injunction, that he not teach Copernicanism.

The exact wording of this item would be central to Galileo’s second trial in 1633. Evidently believing that the election of his admirer Barberini as Pope Urban VIII reopened the possibility of his discussing heliocentric theory — at least as a theory — Galileo published his Dialogue Between Two World Systems, the Ptolemaic and Copernican, with appropriate imprimatur, in 1632. The Dominicans and Jesuits were outraged and it is quite possible that Urban was offended at the sight of one of his favorite Aristotelian arguments in the mouth of the ridiculous character Simplicio. Intrigues were set in motion and Galileo was duly summoned to Rome in 1633 and housed comfortably while awaiting trial — as indeed he was both during and after, and for the rest of his life. At issue was the injunction of 1616. Galileo had obtained a document from Bellarmine abjuring him only from holding or defending heliocentric theory. A separate document produced at the trial stated, in addition, that he was not to teach it either, effectively blocking Galileo from even discussing the matter. This injunction Galileo had clearly violated — assuming that the document in question was genuine (Bellarmine had died in 1621 and so was not available to clarify the matter). “Vehemently suspected of heresy,” he formally recanted and was placed on house arrest for the remainder of his life. He lived comfortably, received visitors, and wrote, dying in 1642.

The second trial of Galileo clearly did not concern Copernicanism per se, the only matter in question being Galileo’s apparent violation of a personal injunction against teaching it. Hence it is not quite accurate to say that Galileo was imprisoned for his heliocentric position, but rather for violating an injunction of the Holy Office. Likewise, the first trial was not particularly concerned with science. Ironically, it is the Church that held to the higher scientific standard of proof than did Galileo, whose favorite argument held that the movement of the tides proved the motion of Earth — an argument unconvincing then and known to be false today. The concern was one of authority to interpret Scripture, a matter of great concern at Trent and a roiling issue since the onset of Protestantism. It was likely a surfeit of caution on the part of the Holy Office that resulted in the embarrassing spectacle of a humiliated Galileo.

And yet, even setting aside the considerable anti-Christian propaganda the event has occasioned, primarily via oversimplification and historical ignorance, as well as the occasional bout of anti-Galileo revisionism (much of it unwarranted and equally simplistic), it cannot be denied that the intellectual world has returned to this ambiguously unsatisfactory event repeatedly, like a tongue to a chipped tooth. The present volume, one of many, ranks among the best and most concise. The authors demonstrate mastery of the material, competence with the written word, and perhaps best of all an appreciation for their modern readers’ concerns and limitations.

The Galileo affair has often generated more heat than light, as its odd and well publicized nature has given occasion for considerable back and forth regarding Galileo’s claims about the motions of the heavens and proper hermeneutical principles vis-à-vis nature and revelation, and the Church’s claims about the nature of epistemology, methodology, and grounding rationale. In Galileo Observed, the authors set about examining all of these claims, fairly, charitably, and generally convincingly.

Additional Recommended References:

Richard J. Blackwell, Galileo, Bellarmine, and the Bible (University of Notre Dame Press, 1991)

Maurice A. Finocchiaro, Retrying Galileo, 1633–1992 (University of California Press, 2005)

Jerome J. Langford, Galileo, Science and the Church, 3rd ed. (University of Michigan Press, 1992)

David C. Lindberg and Ronald L. Numbers, eds., God & Nature: Historical Essays on the Encounter Between Christianity and Science (University of California Press, 1986)

David C. Lindberg and Ronald L. Numbers, When Science and Christianity Meet (University of Chicago Press, 2003)

Ronald L. Numbers, ed., Galileo Goes to Jail and Other Myths about Science and Religion (Harvard University Press, 2009)

Daniel Muth is a nuclear engineer who lives in St. Leonard, Md., and is a frequent contributor to The Living Church.